package xdu.lz.stage2_design_pattern.chapter6_immutable_pattern;

public class StringTest {
    public static void main(String[] args) {
        String str1 = "121";
        String str2 = str1.replace("2", "1");
        System.out.println(str1.getClass()+" "+str1.hashCode());
        System.out.println(str2.getClass()+" "+str2.hashCode());
    }
}
